Thermostatically-controlled circuit closer



Sept. 25, 1928. 1,685,136

' H. n. MoN-rGoMl-:RY

THERMOSTATICALLY CONTROLLED CIRCUIT CLOSER Filed Jan. 19, 1925 ATTORNEY ff Patented Sept. 25, 1928.

msnm' D; noNTGomnnY, on NEW Yonx, N. Y.

THERMosT'A'rICALLY-CONTBOLLED CIRCUIT Ciaosnnh Application med Jnuary 19,- 1925. semi Russia.

The invention relates to a thermostatically controlled circuitcloser of the type-of such devices which are intended to be-screwed into or otherwise attached to a bearing or other machine part, the abnormal heating of which is intended to close a circuit through an alarm or other electrically actuated mechanism. The invention is further identified as being of that type in which the grounding of a metallic part of the thermostat on the part to which it is attached completes the circultand in which the electric current is led to the thermostat by a single electric lead fastened to a binding post carried by the thermostat.v

Such devices are usually mounted in locations where they `are subject to a flow of. oil passing about the same or wherethere 1s likelihood of dust and dirt entering into the interior of the thermostat with a/resulting tendency to short circuit the same or at leastto act deleteriously on the effectiveness andllfe of the device. A u

Accordingly, one of the objects of the 1nvention is to rovide a simplified form of the thermostat o the type outlined and `which can be mounted in position with the circuit clos# ing mechanism housed and prctected from the infiltration of dust, dirt, oil or the llke.

This object is attained by forming the enclosing shell of two parts which when screwed rtogether will seal an enclosed thermostatically actuated circuit closer unit. U

Another object of the invention 1s to provide within the shell operative parts which can be readily replaced in case the devlce should become defectivefor any reason or in case the device should become ino rative by reason of the fact that it has once unctioned. I attain this object by supplying with the thermostat shell a form of insert which will constitute in efl'ect a charging cartridge and which cartridge will contain the necessary thermostatically controlled mechanism for completing the circuit between the binding post on the shell in case of the presence of a temperature sufliciently high to melt the securing fusible solder usually used in devices' of this character.

Another object of the invent-ion is to provide a simple form of thermostat which. can be chgiply constructed and this part1cularly applies not only to the enclosingy shell but also to the small replaceable cartridge which is characterized by the fact that it can be installed quickly` without necessity `of demounting the thermostat shell. v

Various other objects andv advantages ofthe inventlon will be in part obvious from'an inspection of the accompanying drawings and in part -w1ll be more fully set forth in the following particular description `of one form of mechanism embodying my invention, and the invention also consists in certain new and novel features of construtcion and combina'- tion of parts hereinafter set forth and claimed.

In the accompanying drawings the figure 1s asectional view taken axially through a. preferred'embodiment of the invention.

In the following description .and in the claims, parts will be identified by specific names for convenience 'of expression but they are intended to be as generic in their application to similar parts as the art will permit.

In the drawings there is shown a shell 10 provided with a lcentrally positioned outstanding lange 11 and which shell is threaded on o posite sides to provideion one side of the' ange a thread 12 for engaging in a lsuit- V ably tapped hole in the bearings or other :'part of the machine designed to carry the thermostat.v The opposite end of the shell is screw' threaded as shown at 13 and a closing cap 14 engages the threads, 13 and is tightened against the ange 11. The shell 10 is provided with a bore 15 which opens into an enlarged bore 16 formed in the cap 14. It will be understood that the mechanism containing space rovidedby the bores l5 and 16 are air tig t when the two parts of the shell are assembled as shownin the drawings.

The cap 14 is provided at the upper end thereof with a binding post 17 which is in the form lof a headed screw with the head portion 18 exposed in the bore 16 and with the screw insulated from the cap by ineansof an insulatingl bushing 19. The exteriorly projectingr end of the screw 17 is provided with nuts 20 and 21 between which is positioned the conductor 22 which constitutes the lead for conveying electric current to the device.

vLoosely positioned within the bore 15 is al small cylindrical insert or cartridge 23. This cartridge includes a relatively short metal sleeve 24,-open at one end, the bottom end 25 of which constitutes a spring bearing and jects upwardly from the sleeve 24 and extendsl slightly above the upper endof the shell 10 so as to protect the encircled head 27 ot a centrally disposed plunger or circuit closing element 28 and to provide meansorenclosing the plunger and to prevent accidental breaking of the same when thecartridges are stored prior to use in the shell. The plunger 28 is secured at its "lower end to the bearing by means ot `a readily fusible disk 29 of solder. A spring 30 is coiled about the plunger, bears at one end ,against the bearing 25 and bears at its opposite end against the head 2? ot the plunger. This plunger is locked to the solder disk by a peripheral groove and rib connection 3l and the solder disk is locked to the metal sleeve 2li 'by a similar connection 32. llhis prevents creeping ot the plunger in ease the device is used upside down.

operation and assuming that there is a temperature present suiiicient to melt the solder 29, the spring acts on the head to project the saine from the full line into the dotted line position shown in the ligure. The contacting of the plunger head against the screw 9 head 18 acts to complete the circuit from the binding post 17 through theplunger head and through the distended spring to the metallic sleeve 2li which is grounded on the shell 10.

'When the device has once functioned the cap is unscrewed, the used insert thrown away and a new insert dropped into the bore 15 after which the cap is again screwed into position and the device is again ready to function.

While l have shown and described, and have pointed out in the annexedV claims, certain novel features of my invention, it will l be understood that various omissions, substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art withont departing from the spirit o-the invention.

llaving thus described my invention, I c ann:

l.. le thermostat including a metal shell having one end threaded and adapted to be positioned in a support, and having' a bore therein opening through the other end, a readily replaceable insert in the form ot a cylindrical open end cartridge loosely position-ed in said bore and including a base inemher engaging the bottom of the bore, a cirn, -Ab a eloqsing plunger housed within the out- L ner the .cartridge secured at one end by isle solder to said bese member, a spring g r Fd to screw-threaded engagement i therewithv 4lfor closing theopen 'end of the bore and for housing the. inserted cartridge af dust proof casing anda binding post carriedfby and 1nsulatedrom the cap for receiving anextei'- nal conductor, said post having an inner end facing the open 'end of the cartridge and disposed inthepathof movement of the free plunger and adapted to be engaged thereby when projected by the spring.

' 2. A thermostat including a metal shell adapted to have one end threaded'and adapted to have its threaded end positioned a. support,.and having a bore therein opening through the other end, -a readily replaceable insert loosely positioned in said Abore projecting beyond the open end and including a base member engaging the bottom of the bore, a circuit closing plunger housed in the insert and secured at one end byl tusible solderto said base member, aspring bearing on said base member and plungerto proj ect the same when released by the melting ot' the solder, a cap engaging the shell 'or closing the open end o't the bore and for housing the insert in a dust prooil casing and a Ibinding post carried by and insulated from the cap for receiving an external conductor., said post having an inner end disposed in the path 'of movement of the free plunger and adapted to be'engaged thereby when projected by the spring, and said insert includingan insulating sleeve surrounding the plunger and spring to prevent accidental movement of the same against the shell prior to the release of the plunger. 3. A thermostat including a metallic housing, a binding post carried thereby and insulated therefrom, and a readily replaceable insert adapted to be placed in said housing, said insert including a metal sleeve having a closure at one end constituting a spring bearing, a plunger secured to the bearing by a fusible solder and held thereby normally in spaced relation to the binding post, a spring between the plunger and bearing and acting on the melting of the solder to project the plunger into circuit closing engagement with the binding post and an insulating sleeve tted in the metal sleeve and acting to guide the plunger when released axially Yinto engagenient With the binding post.

l.,v An insert tor insertion in the shell oli a thermostat comprising a metallic sleeve closed 'one end and opened at the opposite end, a circuit closing plunger secured rigidly at one end to the closed end of the sleeve bye fusible solder and projecting through and beyond the open end of the metallic sleeve, a long spring er, disposed betrfreen the O ll/ll@ eeve t@ fik-cwi. on

long sleeve ofinsulating material for guiding.-v

i grounding shell, aare laceable insert therefor comprisinga meta ic sleeve closed at one end and opened -at the opposite end, a circuit `closing plunger secured at one end to the closed end of the sleeve by afusible solder and projecting through and beyond. the open end ofthe metallic sleeve, a long spring colled about the plunger, disposed between the closed end of thesleeve and the plunger and acting on the part of the plun er outside of the sleeve to project the free en of the plunger on the melting of the solder, and a sleeve ofinsu'lating material disposed between the plunger and metallic sleeve and -projecting beyond the open end of the sleeve. f

6; In a thermostat, a two-part shell adapted to be-grounded on the member on which it is mounted, said shell provided with an airtight chamber, one of said parts having a single binding post extending axially "therethrough, linsulated therefrom andadapted on its outer end to receive an electric conductor,'an insert constitutin a'cartridge positioned lin said air-tight c amber, said insertincluding thermostatic'ally controlled means for` completing the circuit between the inner ment with the binding post.

' 7. In a thermostatthe combination with a dust tight metallic shell adapted to be grounded provided with a mechanism Acontaining chamber and formed of.. two ports 1n threaded engagement foi-providing access to the chamber, anda conductor leading through said shell into the chamber and in air tight engagement withthe shell, of a thermostaticall 4actuatedV circuit closer. constituting a rep accable,J unit fitted in the chamber and otherwise free of' attachment with the vshell and adapted to engage'the conductor to complete the circuit between the conductor and the shell.-

'8. In a'thermostat, the combination of a.

released by the melting of said solder disk and means for permanently securing one end of the spring electrically to the metal shell.

9. A cylindrical cartridge adapted to fit in the bore-of a thermostatshell and otherwise free of any connections for engaging with the shell, said cartridge comprising a cylindrical metal 'sleeve having a closedr end, a fusible solder disk in said sleeve and engaging said closed end, a cylindrical insulating sleeve fitted in said metalliccasing extending between the solder disk and projecting beyond the open end of the sleeve, a plunger contained within the outlines of the insulating sleeve having one end electrically engaging the closed end and provided with a head at its-other end and a spring bearing at one end on the head and having its other end secured in the'solder disk.

Signed at Gulfpolrt in the county of Harrississippi this 30th day ofl son and State of December, A. D. 1924.

g l HERBERT D. MONTGOMERY.' 

